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11.
Tumor and embryonic cell surfaces are examined in this symposiumwith respect to their roles in cell-cell interactions and inearly development and malignancy. Three sets of studies havebeen recently performed in my laboratory to help elucidate thenature of tumor and embryonic cell surfaces and the means bywhich these cells adhere to each other. We separated an in vivo129/J ascites mouse teratoma into specific subpopuladons ofcells by velocity sedimentation in shallow density gradients.The teratoma consistently separated into two major populations:"large" and "small" cells. Only the large cells displayed "malignant-like"surface characteristics in terms of their agglutinability withcarbohydrate binding lectins. The teratoma cells were also synchronizedin culture with thymidine plus colcemid. In these synchronizedcultures, cellular adhesiveness and glutamine synthetase specificactivity displayed oscillatory patterns with peaks of glutaminesynthetase specific activity occurring just prior to peaks ofadhesivenesss. Also, both glutamine synthetase specific activityand cellular adhesiveness were enhanced by two compounds: actinomycinD and hydrocortisone. Based upon previous work that implicatesL-glutamine in intercellular adhesion, it is not unreasonableto speculate that glutamine synthetase specific activity andcellular adhesiveness may be causally related. The problem ofaltered tumor cell adhesiveness is important because it seems,in part, to be responsible for tumor spread. Finally, the seaurchin embryo system was utilized to identify specific cellsurface carbohydrates that may be involved in intercellularadhesion. In 15 separate experiments with each sugar and with15 different saccharides, D-galactose and N-acetyl-D-galactosaminewere the best inhibitors of rotation-medicated reaggregationof 24-hr sea urchin embryo cells dissociated by removal of divalentcations. ß-galactosidase also inhibited reaggregationof these cells. These results implicate galactopyranosyl-likeresidues in the adhesion of 24-hr sea urchin embryo cells witheach other. 相似文献
12.
STEVEN T. KALINOWSKI 《Molecular ecology resources》2006,6(4):974-979
Deviations from Hardy–Weinberg expectations are frequently a sign of genotyping error. hw‐quickcheck is an easy‐to‐use computer program for detecting departures from Hardy–Weinberg equilibrium. hw‐quickcheck uses exact tests for all of its calculations. These tests include a global test for heterozygote excess/deficiency and genotype‐specific tests. 相似文献
13.
ROSS A. MARKLEIN MATTHEW W. KLINKER KATHERINE A. DRAKE HANNAH G. POLIKOWSKY ELIZABETH C. LESSEY-MORILLON STEVEN R. BAUER 《Cytotherapy》2019,21(1):17-31
Background
Although a preponderance of pre-clinical data demonstrates the immunosuppressive potential of mesenchymal stromal cells (MSCs), significant heterogeneity and lack of critical quality attributes (CQAs) based on immunosuppressive capacity likely have contributed to inconsistent clinical outcomes. This heterogeneity exists not only between MSC lots derived from different donors, tissues and manufacturing conditions, but also within a given MSC lot in the form of functional subpopulations. We therefore explored the potential of functionally relevant morphological profiling (FRMP) to identify morphological subpopulations predictive of the immunosuppressive capacity of MSCs derived from multiple donors, manufacturers and passages.Methods
We profiled the single-cell morphological response of MSCs from different donors and passages to the functionally relevant inflammatory cytokine interferon (IFN)-γ. We used the machine learning approach visual stochastic neighbor embedding (viSNE) to identify distinct morphological subpopulations that could predict suppression of activated CD4+ and CD8+ T cells in a multiplexed quantitative assay.Results
Multiple IFN-γ–stimulated subpopulations significantly correlated with the ability of MSCs to inhibit CD4+ and CD8+ T-cell activation and served as effective CQAs to predict the immunosuppressive capacity of additional manufactured MSC lots. We further characterized the emergence of morphological heterogeneity following IFN-γ stimulation, which provides a strategy for identifying functional subpopulations for future single-cell characterization and enrichment techniques.Discussion
This work provides a generalizable analytical platform for assessing functional heterogeneity based on single-cell morphological responses that could be used to identify novel CQAs and inform cell manufacturing decisions. 相似文献14.
JAMES W. BORRONE J. STEVEN BROWN DAVID N. KUHN JUAN C. MOTAMAYOR RAYMOND J. SCHNELL 《Molecular ecology resources》2007,7(2):236-239
Theobroma cacao L. expressed sequence tags (ESTs) were converted into useful genetic markers for fingerprinting individuals and genetic linkage mapping. Primers were designed to microsatellite‐containing ESTs. Twenty‐two T. cacao accessions, parents of various mapping populations segregating for disease resistance and crop yield characteristics, were tested. Twenty‐seven informative loci were discovered with 26 primer pairs. The number of detected alleles ranged from two to 11 and averaged 4.4 per locus. All 27 markers could be mapped into at least one of the existing F1 or F2 populations segregating for agronomically important traits. 相似文献
15.
LEANNA M. BIRGE STEVEN M. BOGDANOWICZ RICHARD G. HARRISON DANIEL J. HOWARD 《Molecular ecology resources》2007,7(6):1094-1096
Polymorphic di‐, tri‐ and tetranucleotide repeats were examined in Allonemobius to determine whether they could serve as useful markers in studies of sperm precedence, population genetics and hybrid zone structure. Ten microsatellite DNA loci were sufficiently polymorphic to be used for paternity tests and showed no evidence of linkage disequilibrium or deviations from Hardy–Weinberg equilibrium in Allonemobius socius. Nine of 10 of these microsatellites can be amplified from three other Allonemobius species, suggesting that these markers will have widespread utility in this ground cricket genus. 相似文献
16.
PHILIP S WANG MATTHIAS ANGERMEYER GUILHERME BORGES RONNY BRUFFAERTS WAI TAT CHIU GIOVANNI DE GIROLAMO JOHN FAYYAD OYE GUREJE JOSEP MARIA HARO YUEQIN HUANG RONALD C KESSLER VIVIANE KOVESS DAPHNA LEVINSON YOSHIBUMI NAKANE MARK A OAKLEY BROWN JOHAN H ORMEL JOSé POSADA-VILLA SERGIO AGUILAR-GAXIOLA JORDI ALONSO SING LEE STEVEN HEERINGA BETH-ELLEN PENNELL SOMNATH CHATTERJI T. BEDIRHAN üSTüN 《World psychiatry》2007,6(3):177-185
Data are presented on patterns of failure and delay in making initial treatment
contact after first onset of a mental disorder in 15 countries in the World
Health Organization (WHO)''s World Mental Health (WMH) Surveys. Representative
face-to-face household surveys were conducted among 76,012 respondents aged
18 and older in Belgium, Colombia, France, Germany, Israel, Italy, Japan,
Lebanon, Mexico, the Netherlands, New Zealand, Nigeria, People''s Republic
of China (Beijing and Shanghai), Spain, and the United States. The WHO Composite
International Diagnostic Interview (CIDI) was used to assess lifetime DSM-IV
anxiety, mood, and substance use disorders. Ages of onset for individual disorders
and ages of first treatment contact for each disorder were used to calculate
the extent of failure and delay in initial help seeking. The proportion of
lifetime cases making treatment contact in the year of disorder onset ranged
from 0.8 to 36.4% for anxiety disorders, from 6.0 to 52.1% for mood disorders,
and from 0.9 to 18.6% for substance use disorders. By 50 years, the proportion
of lifetime cases making treatment contact ranged from 15.2 to 95.0% for anxiety
disorders, from 7.9 to 98.6% for mood disorders, and from 19.8 to 86.1% for
substance use disorders. Median delays among cases eventually making contact
ranged from 3.0 to 30.0 years for anxiety disorders, from 1.0 to 14.0 years
for mood disorders, and from 6.0 to 18.0 years for substance use disorders.
Failure and delays in treatment seeking were generally greater in developing
countries, older cohorts, men, and cases with earlier ages of onset. These
results show that failure and delays in initial help seeking are pervasive
problems worldwide. Interventions to ensure prompt initial treatment contacts
are needed to reduce the global burdens and hazards of untreated mental disorders. 相似文献
17.
BRAD M. BEBOUT TORI M. HOEHLER BO THAMDRUP DAN ALBERT STEVEN P. CARPENTER MARY HOGAN KENDRA TURK DAVID J. DES MARAIS 《Geobiology》2004,2(2):87-96
Cyanobacterial mats collected in hypersaline salterns were incubated in a greenhouse under low sulphate concentrations ([]) and examined for their primary productivity and emissions of methane and other major carbon species. Atmospheric greenhouse warming by gases such as carbon dioxide and methane must have been greater during the Archean than today in order to account for a record of moderate to warm palaeoclimates, despite a less luminous early sun. It has been suggested that decreased levels of oxygen and sulphate in Archean oceans could have significantly stimulated microbial methanogenesis relative to present marine rates, with a resultant increase in the relative importance of methane in maintaining the early greenhouse. We maintained modern microbial mats, models of ancient coastal marine communities, in artificial brine mixtures containing both modern [] (c. 70 mm ) and ‘Archean’[] (<0.2 mm ). At low [], primary production in the mats was essentially unaffected, while rates of sulphate reduction decreased by a factor of three, and methane fluxes increased by up to 10‐fold. However, remineralization by methanogenesis still amounted to less than 0.4% of the total carbon released by the mats. The relatively low efficiency of conversion of photosynthate to methane is suggested to reflect the particular geometry and chemical microenvironment of hypersaline cyanobacterial mats. Therefore, such mats were probably relatively weak net sources of methane throughout their 3.5 Ga history, even during periods of low environmental levels oxygen and sulphate. 相似文献
18.
DAVID H. SIEMENS RISTON HAUGEN STEVEN MATZNER NICHOLAS VANASMA 《Molecular ecology》2009,18(23):4974-4983
Many species of plants in the wild are distributed spatially in patches, the boundaries of which may occur and change because of a complicated interplay between myriad environmental stressors and limitations of, or constraints on, plant coping mechanisms. By examining genetic variation and co‐variation among marker‐inferred inbred lines and sib‐families of an upland wild mustard species within and just a few meters across a natural patch boundary, we show that the evolution of tolerance to the stressful environment outside the patch may be constrained by allocation to glucosinolate compounds (GS) that are defensive against generalist insect herbivores. Several potential stressors were associated with the patch boundary, but carbon isotope ratios indicated that sib‐families with smaller stomatal apertures maintained performance better in response to late season dry conditions, suggesting that drought was an important stressor. The presence of GS may help explain the characteristic patchy distribution of mustards, a relatively diverse and important plant family. This result challenges one end of the continuum of the long‐standing Plant Apparency hypothesis, which essentially states the opposite causation, that low molecular weight toxins like GS are evolutionary responses of patchy distributions and correlated life‐history traits. 相似文献
19.
20.
CHRIS G. FAULKES GEORGIES F. MGODE STEVEN C. LE COMBER NIGEL C. BENNETT 《Biological journal of the Linnean Society. Linnean Society of London》2010,100(2):337-352
African mole‐rats of the family Bathyergidae are subterranean hystricomorph rodents found throughout sub‐Saharan Africa, where the distributional ranges of the most speciose taxa are divided by the African Rift Valley. In particular, mole‐rats of the genera Heliophobius and Fukomys are distributed widely, and their adaptive radiation appears to have been strongly influenced by the geological process of rifting. As a result, virtually all members of the genus Fukomys occur in locations west of the Rift Valley. However, a small number of isolated populations occur east of the Rift Valley in Tanzania, where Heliophobius is widespread and is the predominant bathyergid rodent. Phylogenetic analysis of mitochondrial cytochrome b sequences of previously unstudied Tanzanian mole‐rats (genus Fukomys) and geographically adjacent populations strongly suggests that vicariance in the Western Rift Valley has subdivided populations of mole‐rats and, together with climatic changes, played a role in the isolation of extralimital populations of Fukomys in Tanzania. Together with molecular clock‐based estimates of divergence times, these results offer strong support for the hypothesis that the observed patterns of cladogenesis are consistent with tectonic activity in the ‘Mbeya triple junction’ and Rungwe volcanic province between Lakes Rukwa and Nyasa. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 337–352. 相似文献